Bag-on-valve systems are described in the prior art. For example, U.S. Pat. No. 3,823,849, assigned to Coster Technologie Speciali SPA, describes a system in which a flexible bag is sealed to the valve and valve housing of an aerosol valve. Likewise, U.S. Pat. No. 7,124,788, assigned to Precision Valve Corporation, describes a similar bag-on-valve arrangement, where the valve has two filling position. One is used to fill the bag with a product and the other position directs propellant into the aerosol container outside the bag.
In a bag-on-valve system, the product to be dispensed is filled into the inside of the bag and a liquefied or compressed gas propellant is filled into the aerosol container outside the bag. When the aerosol valve is actuated, the pressure in the propellant chamber (between the bag and the outer casing of the aerosol container) forces compression of the bag, which drives the product contained in the bag through the aerosol valve.
Disadvantages of bag-on-valve systems include fragility of both the bag and bag/valve combination, and the cost of raw materials used to fabricate the bag. Conventional bags in bag-on-valve systems include a layer of metallic foil which strengthens the bag and provides a barrier to the ingress of gas. However, metal foil is expensive and tends to be brittle. Under pressure, accidental dropping or mishandling of the filled aerosol container can rupture the foil and/or damage the bag/valve combination. Damage to the bag/valve combination may result in separation of the bag to the valve stem.
This invention aims to remedy one or several of the abovementioned disadvantages and to provide a bag/valve assembly with improved toughness while still maintaining excellent sealing and barrier properties.